大型调相机转子气隙偏心故障的复合特征分析

Composite characteristic analysis of rotor air gap eccentricity fault of large scale condenser

在“强直弱交”的大电网背景下,具备动态无功支撑能力的调相机愈发重要,其运行的安全稳定成为未来研究的重点。由于制造、安装、运行等原因,调相机转子气隙偏心故障频发,危害严重。文章以调相机转子气隙偏心故障为研究对象,推导了偏心前后气隙磁密、转子不平衡磁拉力以及定子环流这些复合特征的变化规律,发现偏心后气隙磁密产生偶次谐波,造成转子振动,定子并联支路产生环流,且静态偏心与动态偏心在转子振动频次与支路环流上差异明显,同时以某300 Mvar大型调相机结构参数为依据,利用Ansoft软件建立了有限元模型,仿真验证了故障复合特征分析的正确性,为调相机故障诊断与安全稳定运行提供借鉴和指导。

Under the background of"strong DC and weak AC"power grid,the condenser with dynamic reactive power support capability is becoming more and more important,and its operation safety and stability will become the focus of future research.Due to manufacturing,installation,operation and other reasons,the air gap eccentricity fault of the condenser rotor occurs frequently,thus causing serious harm.Taking the air gap eccentricity fault of the condenser rotor as the research object,this paper deduces the variation rules of the air gap flux density before and after the eccentricity,the unbalanced magnetic pull force of the rotor and the circulating current of the stator.It is found that the air gap magnetic density produces even harmonics after the eccentricity,which causes the rotor vibration,and the stator parallel branches generate circulating current.The static eccentricity and dynamic eccentricity have large difference in the rotor vibration frequency and branch circulating current.Meanwhile,based on the structural parameters of a 300 Mvar large-scale condenser,the finite element model is established by using Ansoft software,and the correctness of the fault compound characteristic analysis is verified by simulation,which provides reference and guidance for the fault diagnosis and safe and stable operation of the condenser.